UNIVERSITY  OF  CALIFORNIA 
College  or  Agriculture 

BERKELEY,  CALIFORNIA 


Agricultural  Experiment  Station 
E.  J.  WlCKSON,  ACTING  Director 


CIRCULAR  No.  24. 


OLIVE  PICKLING. 

VALUE  OF  OLIVES  AS  FOOD.-GATHERING.-SORTING  AND  GRADING.- 
PICKLING  RIPE  OLIVES:  LYE  PROCESS,  WATER  PROCESS.-PICKLING 
GREEN  OLIVES.-PRESERVING  BY  HEATING.-VARIETIES. 


By  FREDERIC  T.  BIOLETTI. 


FIG.  1.     Ascolano  olives. 

The  increasing  favor  with  which  California  pickled  olives  are  received 
throughout  the  United  States,  and  the  consequent  increase  in  demand, 
result  in  the  receipt  of  a  large  number  of  letters  by  the  Agricultural 
Experiment  Station  requesting  information  regarding  methods  of 
pickling.  While  no  new  experimentation  has  been  undertaken  in  this 
matter  by  the  Station  since  the  appearance  of  the  last  bulletin  on  the 


—  2  — 

subject,  the  demand  for  information  makes  it  desirable  to  publish  a 
summary  of  the  results  obtained,  as  the  editions  of  former  bulletins 
are  exhausted. 

While  undoubtedly  improvements  have  been  made  during  the  last 
five  years  in  the  methods  of  pickling,  more  especially  in  the  mechanical 
details,  the  essentials  of  the  methods  remain  the  same  as  when  Bulle- 
tins Nos.  123  and  137  were  published. 

NUTRITIVE    VALUK    OF    OLIVES. 

Pickled  ripe  olives  constitute  an  extremely  nutritious  and  digestible 
form  of  food.  They  contain  a  large  amount  of  oil,  carbohydrates,  and 
some  nitrogenous  matter,  and  in  some  countries  replace  meat  to  a  cer- 
tain extent.  Pickled  green  olives,  such  as  those  imported  from  Spain? 
are,  on  the  contrary,  indigestible  and  contain  much  less  nutriment. 
They  are  made  from  unripe  fruit  and  are,  therefore,  as  far  as  their  use 
as  food  is  concerned,  in  no  way  superior  to  unripe  apples  or  peaches. 
They  are  simply  a  relish  and  to  be  used  in  very  limited  quantities  in 
the  same  way  as  pickled  walnuts  or  cucumbers.  A  meal  of  bread  and 
ripe  olives,  on  the  other  hand,  is  not  only  palatable,  but  nutritious  and 
sustaining,  and  the  amount  eaten  is  to  be  limited  only  by  the  same 
considerations  as  that  of  any  other  good,  wholesome  food. 

The  following  table  of  analyses,  prepared  by  Professor  Jaffa  of  this 
Station,  illustrates  very  forcibly  the  superiority  of  ripe  pickles  over 
green  in  nutritive  value: 

Analyses  of  Edible  Part  of  Ripe  and  of  Green  Pickles. 


Ripe  Pickled  Olives  from  California. 

Queen  Olives 

Medium-sized  Mission. 

Larger 
Watery  Mission. 

(green) 
from  Spain. 

Water 

Oil 

Per  cent. 
64.72 

25.89 

4.28 

5.11 

Per  cent. 
65.45 

25.15 

3.22 

6.18 

Per  cent. 
72.77 

18.81 

2.49 

5.93 

Per  cent. 
78.41 

12  90 

Carbohydrates 

1  78 

Other  matters  

6.91 

The  Queen  olives  were  the  best  of  their  kind  to  be  found  on  the 
market,  and  when  compared  with  the  first  two  samples  of  ripe  pickles, 
which  are  typical  of  good  ripe  Missions,  show  just  one  half  the  amount 
of  nutritive  material.  This  does  not  show  the  whole  difference,  for  there 
is  no  doubt  that  the  nutriment  in  the  ripe  fruit  is  in  a  much  more 
readily  assimilable  form  than  in  the  green.  The  third  sample  was 
grown  on  an  over-irrigated  soil,  and  while  inferior  to  the  first  two, 
is  much  superior  to  the  green  fruit  in  both  quantity  and  quality  of 
nutriment. 


3  — 


GATHERING    THE    OLIVES. 

Whether  olives  are  to  be  used  for  pickling  or  oil-making,  it  is  very 
important  that  they  should  be  picked  carefully  and  at  the  right  time. 
For  green  pickles  they  should  be  picked  very  soon  after  they  obtain 
full  size,  but  before  they  have  begun  to  color  or  soften. 

For  ripe  pickles  they  should  be  gathered  at  the  same  stage  of  ripe- 
ness as  for  oil-making;  that  is,  when  they  contain  the  maximum 
amount  of  oil.  This  is  soon  after  they  are  well  colored,  but  before 
they  have  attained  the  deep  black  which  signifies  over-ripeness.  If  the 
olives  are  gathered  too  green  the  oil  will  be  bitter;  if  too  ripe,  it  will 
be   rancid.     On  account  of  the   different  degrees  of  color  in  different 


FIG. 


The  Garvin  olive-grader. 


varieties  of  olives,  it  is  difficult  to  tell  from  their  appearance  when  they 
should  be  gathered.  When  they  can  be  easily  shaken  from  the  tree 
they  are  ripe  enough.  If  they  commence  to  fall  without  vigorous  shak- 
ing they  are  over-ripe.  For  whatever  purpose  the  olives  are  to  be  used 
they  should  be  carefully  gathered  by  hand.  Rakes  or  sticks  should 
never  be  used,  as  they  bruise  the  fruit  and  break  off  a  great  many  fruit- 
shoots  needed  for  the  following  year.  It  is  well  to  sort  the  olives  as 
they  are  being  picked,  separating  out  the  bruised,  diseased,  or  under- 
ripe fruit. 

GRADING    AND    SORTING. 

It  is  extremely  important  that  all  the  olives  in  each  lot  of  pickles 
should  be  as  nearly  as  possible  uniform  in  character,  in  order  to  facil- 
itate the  process  of  pickling  and  to  produce  an  attractive  appearance. 
Olives  of  different  varieties,  and  even  those  of  the  same  variety  from 


—  4  — 

dissimilar  locations,  should  never  be  mixed.  The  first  sorting  is  done 
while  gathering,  and  the  under-ripe,  over-ripe,  and  injured  fruit  sepa- 
rated from  that  which  is  to  be  pickled.  The  good  fruit  is  then  graded 
according  to  size  by  means  of  a  mechanical  grader.  In  this  way  the 
olives  are  separated  into  different  lots,  which  "will  each  contain  fruit  on 
which  the  different  processes  of  pickling  will  act  uniformly.  A  grader 
adapted  to  handling  soft  fruit,  that  will  not  bruise  the  olives,  must  be 
used.  That  represented  by  Fig.  2  has  been  used  successfully.  After 
the  pickling  process  is  finished  there  will  often  be  a  distinct  difference 
of  color  between  different  olives  of  the  same  lot.  Another  sorting 
according  to  color  is  then  advisable.  This  must  be  done  by  hand,  and ' 
either  two  or  three  colors  may  be  separated — dark  and  light  or  black, 
medium,  and  greenish,  according  to  the  variety. 

Unfortunately  the  consumer  has  acquired  a  taste  for  jet  black  olives 
and  will  accept  a  lighter  olive  only  at  a  lower  price.  This  has  led  to 
more  or  less  questionable  practices  which  have  for  their  object  the 
retaining  of  the  natural  dark  color  of  some  varieties,  and  the  coloring 
of  those  which  are  naturally  light  in  color.  It  is  very  seldom  possible 
to  put  a  perfectly  black  pickled  olive  on  the  market  without  the  use  of 
some  dye  or  mordant,  which,  even  if  harmless,  certainly  does  not 
improve  the  flavor  or  wholesomeness  of  the  food.  This  practice  would 
be  unnecessary  if  the  consumer  could  be  taught  that  some  of  the  best 
varieties  of  olives  are  naturally  light  gray  or  brownish  green  in  color 
after  pickling,  and  that  any  black  olive  is  to  be  suspected  of  treatment 
with  substances  that  are  unnecessary  for  the  production  of  the  best 
quality. 

PICKLING    RTPE    OLIVES. 

The  successful  production  of  pickled  olives  is  a  matter  of  experience 
and  depends  almost  altogether  on  the  individual  judgment  and  skill  of 
the  producer.  No  method  can  be  given  which  is  suitable  to  all  cases, 
and  the  best  method  must  be  modified  according  to  the  nature  of  the 
olives  to  be  treated.  The  following  scheme,  therefore,  is  to  be  con- 
sidered as  a  mere  outline,  to  be  carefully  adapted  and  modified  by  the 
operator  at  each  stage  of  the  process: 

Lye  Process. — 1.  Place  the  olives  in  a  solution,  composed  of  two 
ounces  of  potash  lye  to  one  gallon  of  water,  for  four  hours.  Repeat 
this  once,  or  twice,  if  necessary  to  sufficiently  remove  the  tartness. 

2.*  Rinse  the  olives  thoroughly  and  replace  the  lye  solution  with 
fresh  water.  Change  the  water  twice  a  day,  until  the  potash  has  been 
removed  from  the  olive,  as  judged  by  the  taste. 

3.  Replace  the  water  with  brine  composed  of  four  ounces  of  salt  to  a 

gallon  of  water  and  allowed  to  stand  two  days. 

*Professor  Hilgard  recommends  the  use  of  weak  brine  from  the  first;  that  is,  as  soon 
as  the  lye  solution  is  removed. 


—  5  — 

4.  Put  in  brine  of  six  ounces  of  salt  to  a  gallon  for  seven  days. 

5.  Put  in  brine  of  ten  ounces  per  gallon  for  two  weeks. 

6.  Put  finally  into  a  brine  containing  fourteen  ounces  of  salt  to  the 
gallon  of  water. 

In  order  to  make  this  process  a  success  the  following  considerations 
should  be  kept  in  view: 

1.  Great  care  should  be  taken  not  to  allow  the  olives  to  come  in  con- 
tact with  anything  that  will  injure  their  flavor.  The  vats  or  other 
receptacles  used  for  pickling  should  be  perfectly  clean,  odorless,  and 
tasteless.  Earthenware  is  the  best  material,  but  it  is  usually  cheaper 
and  more  convenient  to  use  wooden  receptacles  thoroughly  treated  with 
boiling  water  and  soda  until  they  are  sterilized  and  all  taste  of  the 
wood  removed.  Any  wood  (such  as  pine)  with  strong  taste  should  not 
be  used.  The  vats  should  be  provided  wTith  a  removable  wooden  grating, 
fastened  one  or  two  inches  from  the  bottom,  and  a  close-fitting,  floating 
wooden  cover  to  prevent  access  of  air,  which  spots  the  fruit.  On  top  of 
the  vats  should  be  placed  a  cover  of  thick  cloth  or  of  wood  to  exclude 
the  light  and  dust.  Each  vat  should  be  provided  at  the  bottom  with  a 
wooden  spigot  for  drawing  off  the  solutions.  The  thickness  of  the  layer 
of  olives  should  not  be  more  than  two  feet,  or  less  with  soft  varieties. 

2.  It  is  best  to  use  good  potash  lye.  Some  of  the  brands  of  lye  are  so 
impure  that  it  k  impossible,  without  a  chemical  analysis,  to  tell  within 
forty  per  cent  how  strong  the  lye  solution  actually  is  when  made  up. 
"  Greenbank  lye  "  has  been  found  the  most  reliable,  and  may  be  con- 
sidered as  one  hundred  per  cent  pure  when  making  up  the  solution. 

Impure  lyes  are  often  used  with  success,  but  it  is  necessary  to  use 
more  of  them.  The  principal  adulterant  is  common  salt,  and  if  soft  or 
over-ripe  olives  are  being  pickled  this  may  be  an  advantage,  as  it  keeps 
the  fruit  firm.  If  we  have  pure  lye,  however,  we  can  add  the  salt  if 
necessary  and  leave  it  out  if  we  do  not  need  it.  As  salt  is  much  cheaper, 
than  lye  it  is  better  to  buy  it  separately  and  not  to  pay  the  price  of  lye 
for  it  as  we  do  when  we  buy  impure  grades. 

The  length  of  time  which  the  olives  should  be  left  in  the  lye,  and  the 
number  of  times  the  lye  should  be  renewed,  can  only  be  determined 
for  each  variety  and  each  locality.  The  object  is  to  extract  the  tartness 
of  the  olive,  and  at  the  same  time  to  soften  the  skin  sufficiently  to 
allow  the  tart  or  bitter  substances  to  be  soaked  out  in  the  subsequent 
treatment  with  pure  water.  The  tougher  and  thicker  the  skin  of  the 
olive,  and  the  more  intense  the  tartness,  the  longer  must  the  lye  treat- 
ment be  continued.  The  lye  is  sometimes  made  twice  as  strong  as 
recommended  above,  and  the  treatment  correspondingly  shorter,  but 
the  results  are  not  so  good.  Just  enough  lye  solution  should  be  used 
to  exactly  cover  the  olives,  and  occasionally,  during  the  soaking,  some 


—  6  — 

of  the  solution  should   be  drawn  off  below  and  poured  on  top  to  insure 
an  equal  treatment  of  all  the  fruit. 

3.  Only  the  very  purest  water  should  be  used,  both  for  the  lye  solu- 
tion and  for  the  subsequent  soaking.  Canal  and  river  water,  or  any 
water  that  contains  a  great  deal  of  organic  matter,  should  never  be 
used,  unless  it  is  practicable  to  boil  it  first.  Distilled  water,  such  as 
can  sometimes  be  obtained  by  condensing  the  waste  steam  from  a 
boiler,  is  the  best,  on  account  of  its  purity  and  its  greater  extractive 
power,  provided  of  course  it  be  free  from  oily  flavors.  The  length  of 
time  during  which  the  soaking  in  pure  water  should  be  continued  varies 
very  much  in  accordance  with  the  character  of  the  fruit.  If  the  olives 
are  firm  and  show  no  signs  of  becoming  soft  it  should  be  continued 
until  the  tartness  is  sufficiently  extracted.  This  will  vary  usually 
between  ten  and  twenty  days.     The  moment  that  the  olives  begin  to 


Cloth  Cover. 
Floating  Cover 


Olives. 


Wooden  Grating. 


FIG.  3.    Pickling  vat. 

show  signs  of  softening,  however,  they  should  be  placed  in  weak  brine, 
even  though  the  tartness  has  not  all  disappeared.  What  remains  can 
then  be  extracted  by  the  brine,  which  should  be  changed  two  or  three 
times,  as  may  be  necessary.  It  is  not  necessary  to  change  the  brine 
quite  so  often  as  the  pure  water,  once  in  two  days  being  generally 
sufficient. 

If  the  olives  are  soft  at  first,  before  treatment  with  lye,  or  if  they  are 
of  a  kind  that  softens  rapidly  in  the  lye,  it  is  necessary  to  use  brine 
from  the  beginning,  either  immediately  after  treatment  with  lye,  or, 
in  extreme  cases,  with  the  lye.  This  method,  suggested  by  Professor 
Hilgard,  has  been  used  with  marked  success.  The  lye  solution  in  this 
case  should  be  made  by  adding  two  ounces  (or  less,  if  the  olives  are  not 
very  bitter)  of  lye  and  four  ounces  of  salt  to  each  gallon  of  water.  As 
the  lye  acts  much  more  slowly  when  used  in  combination  with  salt,  it 
may  be  allowed  to  stay  on  the  olives  for  a  longer  time  without  injury — 
eight  to  twelve  hours,  or  even  more.  This  lye  and  salt  solution  tends 
to  harden  and  shrink  the  olives.  The  shrinkage,  which  occurs  when 
brine  is  used  from  the  beginning  on  naturally  soft  olives,  is  not  a  disad- 


—  7  - 

vantage  if  not  carried  too  far,  as  such  olives  are  generally  too  watery 
to  be  palatable  or  to  keep  well.  They  can,  moreover,  if  shrunk  too 
much,  be  made  plump  again  by  a  few  treatments  with  pure  water  before 
being  put  finally  into  brine. 

The  first  salting  must  be  done  very  gradually  and  carefully,  in  order 
to  prevent  shrinkage  and  wrinkling  of  the  fruit.  For  this  reason,  grad- 
ually increasing  strengths  of  brine  must  be  used,  a's  described,  and  the 
olives  left  long  enough  in  each  to  be  thoroughly  penetrated. 

In  these  operations  no  sign  of  scum  or  slime  should  be  allowed  to 
accumulate  on  the  olives,  the  vats,  or  the  covers.  This  is  of  especial 
importance  during  the  treatment"  with  plain  water.  On  the  first 
signs  of  sliminess  around  the  sides  of  the  vats,  where  it  appears  first, 
the  latter  should  be  emptied  and  thoroughly  brushed  and  scalded 
before  replacing  the  olives. 

Pure-Water  Process. — The  best  pickled  olives  are  made  without  the 
use  of  lye,  but  this  process  is  only  practicable  with  olives  such  as  Asco- 
lano  and  Columbella,  the  tartness  of  which  is  easily  extracted,  and  where 
the  water  is  extremely  pure  and  plentiful,  and  even  then  it  is  very  slow 
and  tedious.  It  differs  from  the  last  process  only  in  omitting  the  pre- 
liminary lye  treatment.  The  olives  are  placed  from  the  beginning  in 
pure  water,  which  is  changed  twice  a  day  until  the  bitterness  is  suffi- 
ciently extracted.  This  requires  from  forty  to  sixty  days  or  more.  The 
extraction  is  sometimes  hastened  by  making  two  or  three  shallow, 
longitudinal  slits  in  each  olive;  but  this  modification,  besides  requiring 
a  large  amount  of  expensive  handling,  renders  the  fruit  peculiarly  sus- 
ceptible to  bacterial  decay  and  softening. 

PICKLING   GREEN    OLIVES. 

Green  olives  can  be,  and  have  been,  pickled  in  California  by  exactly 
the  same  methods  used  for  ripe  olives,  and  when  treated  in  this  way 
leave  nothing  to  be  desired  as  regards  flavor  and  keeping  qualities. 
They  have,  however,  the  defect,  fatal  commercially,  of  losing  their 
bright-green  color  during  the  process  of  pickling,  or  shortly  afterwards. 
Practically  all  the  unripe  olives  prepared  in  California  turn  an  unsightly 
brown  or  gray,  and  have  for  this  reason  been  unmarketable  in  competi- 
tion with  the  imported  Spanish  olives,  which  usually  retain  their  bright- 
green  or  yellowish-green  color,  even  when  taken  from  the  brine  and 
exposed  to  the  air  for  a  considerable  time  on  the  counters  of  the  grocers. 
In  spite  of  the  opinions  of  connoisseurs  and  of  the  analyses  of 
chemists,  which  show  that  the  ripe  pickled  olives  are  not  only  more 
pleasing  to  the  cultivated  palate,  but  also  more  digestible  and  nutritious, 
the  fact  remains  that  the  favorite  olives  with  the  average  consumer,  and 
those  for  which  the  trade  can  afford  to  pay  the  highest  price,  are  the 


—  8  — 

large  green  "  Queen  "  olives  of  Spain.  These  are  the  product  of  several 
large-fruited  varieties,  pickled  (when  green)  by  processes  which  are 
trade  secrets  of  the  Spanish  producers,  or  which,  having  been  devised 
for  local  conditions,  are  inapplicable  here. v  The  finest  and  largest  are 
made  from  a  variety  called  Sevillano,  though  other  large  kinds  are  used; 
and  doubtless  any  large  olive  such  as  Macrocarpa, ,  True  Picholine, 
Santa  Catarina,  and  Ascolano,  could  be  successfully  marketed,  if  cured 
in  the  same  way.  Now  that  these  varieties  are  beginning  to  be  pro- 
duced in  California  in  notable  quantities,  it  is  important  that  some  way 
of  preparing  them  should  be  found  that  will  enable  them  to  hold  their 
own  against  their  imported  rivals. 

A  series  of  experiments,  detailed  in  Bulletin  No.  137  of  this  Station, 
demonstrated  that  it  is  possible  to  produce  green  pickled  olives  which 
will  retain  their  color  for  at  least  twelve  months  by  the  lye-and-salt 
method  of  treatment,  if  properly  modified  and  controlled.  The  color  is 
preserved,  so  that  exposure  to  the  air  after  the  completion  of  the  pick- 
ling process  does  not  seriously  affect  the  color  for  some  time.  The  fol- 
lowing process,  based  on  these  experiments,  is  recommended: 

Choice  of  Fruit. — Only  large-fruited  varieties  should  be  used,  as  the 
small  green  pickles  bring  a  very  inferior  price.  The  olives  should  be 
gathered  as  soon  as  they  have  reached  full  size  and  before  they  have 
colored  notably.  A  slight  pink  color  on  one  side  does  little  harm,  as  it 
disappears  during  the  process,  but  olives  which  have  reached  the  stage 
of  ripeness  indicated  by  this  first  change  of  color  will  probably  have 
less  of  the  bright  green  than  if  gathered  earlier.  No  two  varieties 
should  be  pickled  together,  and  the  olives  should  be  graded  into  three 
or  four  sizes.  The  reason  for  this  is  that  different  varieties  and  differ- 
ent sizes  are  almost  sure  to  require  different  strengths  of  lye  solution, 
and  it  is  therefore  impossible  to  attain  the  best  results  unless  this  selec- 
tion is  made.  The  proper  strength  of  lye  solution  to  use  in  each  case 
is  best  determined  by  a  preliminary  trial,  as  follows: 

Preliminary  Trial. — Take  a  series  (about  six)  of  pint  preserving  jars 
and  fill  them  with  the  olives  to  be  tested.  Pour  into  them,  respectively, 
a  i°/Q,  1%,  U%,  2%,  2i%  and  3%  lye-solution,  sufficient  to  completely 
cover  the  fruit.  At  the  end  of  forty-eight  hours  examine  them.  (It  has 
been  found  that  a  sufficiently  strong  lye-solution  will  extract  the  acid 
and  bitter  principles  of  even  very  bitter  olives  in  forty-eight  hours.) 
At  the  end  of  this  time  some  of  the  weaker  lye-solutions  will  be  found 
to  have  been  neutralized;  that  is  to  say,  all  the  lye  will  have  been  used 
up  in  acting  upon  the  acids  of  the  fruit.  This  will  be  made  evident  by 
the  lack  of  the  slimy  feeling  which  the  fingers  have  when  dipped  into  a 
lye-solution  and  rubbed  together.  Suppose  that  the  i%,  1%,  and  \\% 
solutions  are  neutralized,  and  that  the  2%  still  has  a  slight  slimy  feel- 


ing.  This  will  show  that  a  2%  solution  is  a  little  stronger  than  is 
necessary  to  neutralize  all  the  bitter  or  acrid  matters  in  the  sample 
tested.  If,  now,  we  use  a  2%  solution  in  curing  the  bulk  of  the  olives 
from  which  the  sample  was  taken,  we  are  able  to  preserve  the  green 
color  perfectly.  If  we  use  a  somewhat  stronger  solution,  say  a  2£%, 
the  color  will  bleach  out  a  little;  while  if  we  use  a  much  weaker  solu- 
tion, say  a  l%,the  green  will  change  to  that  disagreeable  gray  or  brown 
which  we  wish  to  avoid. 

Process. — The  appropriate  strength  of  lye-solution  having  been 
determined,  the  olives  are  placed  in  convenient  receptacles,  where  they 
can  be  treated  with  a  minimum  exposure  to  the  light  and  air.  For 
this  purpose  fifty-gallon  barrels  with  very  large  bungholes  (four  or  five 
inches  in  diameter)  and  spigots  are  useful.  After  filling  the  barrels 
with  olives,  the  lye,  of  the  strength  determined  in  the  preliminary  trial, 
is  poured  in.  Each  barrel  should  be  quite  full  of  olives,  and  sufficient 
lye-solution  should  be  put  in  to  come  flush  with  the  bunghole.  At  the 
end  of  forty-eight  hours  the  lye  should  be  drawn  off,  the  olives  quickly 
wTashed  with  two  changes  of  fresh  water,  and  the  barrels  filled  immedi- 
ately with  a  2%  salt-solution.  This  brine  should  be  replaced  succes- 
sively with  a  4%  and  8%,  and  finally  a  12%  solution,  in  the  last  of 
which  the  pickles  remain  permanently.  The  successive  brines  should 
be  allowed  to  act  for  from  forty-eight  to  seventy-two  hours  each,  accord- 
ing to  the  size  of  the  olives;  the  larger  sizes  requiring  more  time  for 
the  brine  to  penetrate  and  to  displace  the  excess  of  lye  which  remains. 
The  whole  process  will  thus  take  from  ten  to  fourteen  days. 

Absence  of  Air. — The  essential  part  of  the  process  is  to  avoid  exposing 
the  olives  to  the  air  during  the  pickling,  until  all  the  bitterness  and 
acid  are  completely  neutralized  by  the  lye.  After  this  the  green  color 
seems  to  be  fixed,  and  exposure  to  the  air  does  not  change  it  much, 
though  it  is  well,  all  through  the  process,  to  avoid  leaving  the  olives 
uncovered  by  liquid  any  longer  than  necessary. 

As  different  varieties  of  olives,  and  even  the  same  variety  in  different 
seasons  and  from  different  localities,  differ  very  much  in  bitterness, 
the  importance  of  treating  each  variety  separately  is  evident,  as  each 
will  require  lye-solutions  of  different  strength  to  neutralize  it.  Very 
bitter  olives,  such  as  Mission,  Sevillano,  Manzanillo,  and  True  Picholine, 
require  solutions  containing  from  l-£%  to  2%  of  pure  potash  lye,  while 
olives  containing  little  bitterness,  such  as  Ascolano  and  Columbella, 
require  only  from  \°/0  to  1%  solutions.  As  many  of  the  commercial 
lyes  are  far  from  pure,  some  containing  not  more  than  fifty  per  cent  of 
potash,  the  number  of  preliminary  tests  must  usually  be  at  least  six, 
as  indicated  above.  Preliminary  tests  conducted  as  described  do  not 
require  an  analysis  of  the  lye,  though  it  is  probable  that  lyes  contain- 


—  10  — 

ing  a  large  amount  of  common  salt  would  act  more  slowly;  and  with 
such  lyes  a  treatment  exceeding  forty-eight  hours  might  be  necessary. 
To  facilitate  the  preparation  of  the  different  strengths  of  solutions, 
it  is  convenient  to  remember  that,  as  a  gallon  of  water  weighs  128 
ounces,  one  and  a  quarter  ounces  of  solid  lye  to  the  gallon  of  water  is 
equal  (in  round  numbers)  to  one  per  cent;  or  that  one  pound  of  such 
lye  will  make  twelve  and  a  half  gallons  of  one  per  cent  solution. 

PRESERVING   OLIVES    BY    HEAT. 

However  carefully  the  processes  of  pickling  are  carried  out  the  olives 
will  only  keep  for  a  limited  time.  They  usually  remain  in  good  condi- 
tion for  about  six  months  when  kept  in  a  strong  brine,  and  the  best 
may  last  in  fair  condition  for  a  few  months  longer.  Few  olives  are 
good  when  kept  in  the  ordinary  way  for  twelve  months.  By  that  time 
they  usually  become  moldy  or  slimy,  or  acquire  a  disagreeable  decayed 
taste  or  smell,  even  when  the  brine  contains  12%  of  salt. 

It  was  shown  by  the  experiments  detailed  in  Bulletin  No.  137  that  by 
a  proper  heating  of  the  olives  after  pickling  their  keeping  qualities  could 
be  much  improved.  Ripe  pickled  olives,  heated  to  175°F.,  kept  perfectly 
for  thirty-two  months.  By  heating  them  still  higher  in  sealed  cans  or 
bottles  they  can  be  kept  indefinitely  with  as  great  facility  as  any  other 
food  product.  The  heating  does  not  injure  the  flavor  and  the  texture, 
but,  on  the  contrary,  improves  them.  Olives  preserved  by  heating  do 
not  require  such  strong  brine,  and  it  is  only  necessary  to  add  as  much 
salt  as  the  palate  requires.  Ordinary  olives  require  soaking  to  remove 
part  of  the  salt  before  they  are  eaten.  The  heating  causes  some  of  the 
coloring  matter  to  diffuse  out  into  the  brine,  so  that  the  olives  are  made 
a  little  lighter  colored.  With  time,  however,  the  coloring  matter 
diffuses  out  in  the  same  way  from  unheated  olives,  so  that  at  the  end 
of  a  year  the  heated  olives  are  actually  darker  in  color  than  the 
unheated. 

VARIETIES    OF    OLIVES   FOR   PICKLING. 

The  commonest  variety  of  olive  grown  in  California  both  for  oil  and 
pickles* is  the  Mission,  so  called  because  it  was  the  variety  found  in  the 
gardens  of  the  old  Spanish  missions.  It  is  hardy,  a  regular  bearer,  and 
less  subject  than  other  large  varieties  to  dry  and  soft  rot.  It  has  the 
deep  color  and  typical  pointed  olive  shape  which  the  market  prefers. 
It  is  smaller,  however,  and  of  poorer  quality  as  a  pickling  olive  than 
several  other  varieties  which  have  done  well  in  a  few  orchards  in 
California. 

The  largest  olives  of  all  are  the  Ascolano  and  the  Sevillano.  The 
former  is  an  Italian  olive  as  large  as  a  French  prune  and  very  much 
like  one  in  shape  and  appearance.     It  makes  a  ripe  pickle  of  excellent 


—  11  — 

quality,  but  is  lacking  in  color.  When  pickled  green  it  is  too  pale  in 
color,  but  this  might  be  remedied  by  gathering  more  unripe. 

The  Sevillano  is  the  Spanish  variety  from  which  the  best  "Queen" 
olives  of  Spain  are  made.  It  is  almost  as  large  as  the  Ascolano,  and 
has  the  advantage  of  deep  black  color  and  typical  olive  shape.  In 
appearance  it  resembles  a  very  large  Mission  olive.  It  is  most  excel- 
lent for  both  ripe  and  green  pickles,  though  a  little  inferior  in  flavor  to 
the  Manzanillo  and  the  Gordal. 

Next  in  size  to  these  two  are  the  Macrocarpa,  Polymorpha,  Picholine 
d'Aix,  and  Amygdalina.     These  are  intermediate  in  size  between  the 


FIG.  4.    Mission.     (Single  olive,  natural  size.) 

Sevillano  and  the  Mission.  The  first  two  are  very  subject  to  soft  rot, 
and  the  last  has  been  tested  very  little  here.  The  Picholine  d'Aix  is 
apparently  the  best  of  the  four,  and  makes  an  excellent  ripe  pickle. 
It  has  a  very  free  pit  and  is  used  in  France  for  making  stuffed  olives. 
The  Obliza,  Manzanillo,  and  Gordal  have  been  tested  in  various 
localities  and  in  a  few  have  given  satisfaction.  The  first  two  are  sub- 
ject to  soft  rot  in  the  interior  valleys.  The  last  two  produce  ripe 
pickles  of  the  best  quality,  being  superior  in  flavor  and  texture  to  any 
which  have  been  tried  in  California.  They  are  about  the  same  size  or 
a  little  larger  than  the  Mission,  but  are  not  of  so  desirable  a  shape. 
The  Manzanillo  especially,  as  its  name  indicates,  is  short  and  apple- 
shaped. 


FIG.  5.    True  Picholine. 


FIG.  8.    Manzanillo. 
(Figs.  6,  7,  8,  natural  size.) 


FIG.  9.    Mission. 


FIG.  10.    Sevillano. 


FIG.  11.    Nevadillo. 


FIG.  12.    Polymorpha. 


